MPJDEPEND-4: Exception in jsl when there are no cyclic dependencies

git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@291026 13f79535-47bb-0310-9956-ffa450edef68

jdepend/src/plugin-resources/jdepend.jsl

@@ -256,7 +256,7 @@
           <jdepend:nav/>
           <x:set var="packages" select="Cycles/Package"/>
           <j:choose>
-            <j:when test="${size(packages) == 0}">
+            <j:when test="${packages == null || size(packages) == 0}">
               <p>There are no cyclic dependencies.</p>
             </j:when>
             <j:otherwise>